Double pin tumbler cylinders of the type described above are known for example from U.S. Pat. No. 3,974,671. Described there is a cylinder housing in which the housing pins and their springs are located in separate chambers within the housing and in which the cylindrical housing is subdivided into, for example, a number of sintered, pressed parts for the purpose of reducing the cost of production and increasing the security against tampering.
It has been shown in practice however that the assembly of tumbler cylinders from separately produced parts represents great difficulty due to the variation of the dimensions of the individual parts, resulting in cylinder cores which tend to jam in the cylinder and which present excessive resistance to the insertion and removal of the keys.